I have a Jacuzzi and just dealt with the FL1 error over the past week. It was my circulation pump and after replacing it, everything is back in working order. On mine, the circulation pump was the first pump to turn on when the breaker is turned on. It is a low volume pump but will make some small bubbles upon start up. You can also tell if the cirulation pump is working by putting your hand over the filter inlet with the grate or cover over it. If there is no suction, then the pump isn't functional. I read where some people were able to take their pump apart and had calcium deposits inside that they cleaned off and put it back in and it worked. I didn't see any deposits with my pump so I just bought a new one. Hope this helps.